BATTERY COVERS AND POWER BATTERIES

A battery cover includes a top cover assembly and an insulating support. The top cover assembly can be fixedly connected with a case to form an accommodation space for accommodating a core, and the top cover assembly can be welded with a tab on the core. The insulating support can be accommodated in the accommodation space. The insulating support and the top cover assembly form an accommodation cavity for accommodating the tab, and the insulating support is provided with a notch for the tab to pass through.

TECHNICAL FIELD

The present application relates to battery technologies, for example, to battery covers and power batteries.

BACKGROUND

A battery includes a case, a core with at least one tab, and a cover. The core is accommodated in the accommodation space formed by the case and the cover. When assembling, the core is accommodated in the case, and the tab is flattened by ultrasonic welding and then laser welded together with the cover. Then, the cover is fixed on the case, and the tab is bent between the cover plate and the core, so as to maximize the utilization of the internal space. However, when the cover is closed, a reshaped part of the tab may be inserted into the core backwards, resulting in a short circuit.

SUMMARY

In view of the above, one or more embodiments of the present application provide a battery cover, including: a top cover assembly capable of being fixedly connected with a case to form an accommodation space for accommodating a core, and capable of being welded with a tab on the core; and an insulating support capable of being accommodated in the accommodation space, wherein the insulating support and the top cover assembly form an accommodation cavity for accommodating the tab, and the insulating support is provided with a notch for the tab to pass through.

In addition, one or more embodiments of the present application provide a power battery, including a case, a core and a battery cover, wherein the battery cover comprises a top cover assembly and an insulating support; the top cover assembly is fixedly connected with the case to form an accommodation space where the core and the insulating support are accommodated; the top cover assembly is welded with a tab on the core; and the insulating support and the top cover assembly form an accommodation cavity where the tab is accommodated, and the insulating support is provided with a notch for the tab to pass through.

DETAILED DESCRIPTION

In the description of the present application, unless otherwise expressly specified and limited, the terms “coupled” “connected” and “fixed” shall be understood in a broad sense, for example, they may be fixed connection, removable connection, or integral. They may be mechanical connection or electrical connection. They may be directly connected or indirectly connected through intermediate medium. They may be internal connection of two elements or interaction of two elements. Those of ordinary skilled in the art may understand the specific meaning of the above terms in the present application in specific circumstances.

In the present application, unless otherwise expressly specified and defined, a first feature “above” or “below” a second feature may include the first feature directly contacts with the second feature, or it may include the first feature does not directly contact with the second feature but through another feature between them. Also, the first feature “above,” “upper” and “over” the second feature includes the first feature directly above and obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature “below,” “lower” and “under” the second feature includes the first feature directly below and obliquely below the second feature, or merely indicates that a horizontal height of the first feature is less than the second feature.

One or more embodiments of the present application provide a power battery. As shown inFIGS.1-5, the power battery includes a case3, a core4and a battery cover. In addition, one or more embodiments of the present application provide a battery cover including a top cover assembly1and an insulating support2. The top cover assembly1can be fixedly connected with the case3, and the case3and the top cover assembly1form an accommodation space for accommodating the core4. The top cover assembly1can be welded with a tab41of the core4. The insulating support2can be accommodated in the accommodation space. The insulating support2and the top cover assembly1form an accommodation cavity P for accommodating the tab41. The insulating support2is provided with a notch23for the tab41to pass through.

When the power battery is provided with the battery cover, the core4and the insulating support2are accommodated in the accommodation space. The tab41of the core4is welded with the top cover assembly1. The tab41is accommodated in the accommodation cavity P. That is, the accommodation cavity P provides an accommodation space for the tab41, thereby preventing the tab41from being spread between the core4and the top cover assembly1. Thus, the structure of power battery is stable. In addition, the insulating support2effectively isolates the tab41from the core4, thereby preventing a reshaped part of the tab41due to reshaping of the tab41from being inserted into the core4backwards. Thus, a short circuit can be avoided, improving safety and reliability of the power battery, and improving the yield rate of the power batteries.

In one or more embodiments, the power battery may a blade battery or another battery.

In one or more embodiments, as shown inFIGS.3and7, the top cover assembly1includes a cover plate11, an upper plastic part12, a lower plastic part13, and a terminal14. The cover plate11can be fixedly connected to the case3. The upper plastic part12and the lower plastic part13are respectively fixed on opposite sides of the cover plate11. The lower plastic part13is connected with the insulating support2. The terminal14extends through the lower plastic part13, the cover plate11and the upper plastic part12. The terminal14can be welded with the tab41. The cover plate11is generally an aluminum plate. With the upper plastic part12and the lower plastic part13arranged, a short circuit can be prevented.

In addition, the terminal14has a lower terminal block141disposed on a side facing the core4. The lower terminal block141has a relatively large cross-sectional area, so as to increase an area of connection between the terminal14and the tab41and improve structural reliability. In one or more embodiments, the notch23is disposed toward the lower terminal block141at the end of the terminal14, so that the tab41can pass through the notch23after being welded with the lower terminal block141. In one or more embodiments, the lower plastic part13is provided with a recess132. The lower plastic part13and the insulating support2form the accommodation cavity P. In one or more other embodiments, the insulating support2may be provided with the recess132to form the accommodation cavity P. In one or more yet other embodiments, each of the lower plastic part13and the insulating support2may be provided with the recess132to form the accommodation cavity P. The arrangement may be determined according to the actual situation and is not limited. For example, the lower plastic part13may not be retained in a region corresponding to the lower terminal block141, so as to prevent the lower plastic part13from affecting the welding of the lower terminal block141with the tab41. In one or more embodiments, the accommodation cavity P is a cuboid-shaped cavity, which increases the accommodation space and facilitates the arrangement of the tab41. For example, a length of the notch 23=the width of the tab 41+2˜5 mm, and a depth of the notch 23=the thickness of the tab 41+1˜2 mm.

In one or more embodiments, as shown inFIG.6, the notch23is provided with a fillet or a rounded corner231along a thickness direction of the insulating support2, so as to avoid forming of a sharp edge at the notch23, which can effectively prevent the tab41from being cut by the sharp edge in a high-intensity vibration application scenario of the core4. By way of example, a size of the fillet or rounded corner231may be, but not limited to, 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, or 1.0 mm.

In one or more embodiments, a height of the lower plastic part13is determined according to the thickness of the reshaped tab41to be accommodated. The size of the accommodation cavity P is set according to the actual situation, so as to ensure that an energy density can be increased as much as possible under the condition of accommodation of the tab41. For example, the height of the lower plastic part 13=the number of layers of the tab41*the thickness of the foil*3*a correction coefficient. When a positive tab41is to be accommodated, the correction coefficient can be adjusted within a range of 1.5-2.5. When a negative tab41is to be accommodated, the correction coefficient can be adjusted within a range of 1.2-2.0.

In one or more embodiments, as shown inFIG.6andFIG.7, the insulating support2is detachably connected to the top cover assembly1, which can prevent the insulating support2from falling off during the process of assembling the core4, improve the connection stability and reliability, and facilitate disassembly. For example, the insulating support2is disposed to cover the lower plastic part13, and the insulating support2is clamped with the lower plastic part13. In one or more embodiments, the lower plastic part13is provided with a slot131, and the insulating support2is provided with a fastener24that can be clamped to the slot131. In other embodiments, the insulating support2is provided with a slot131, and the lower plastic part13is provided with a fastener24. For example, a number of groups of slots131and a number of groups of fasteners24are provided, and the number may be, but not limited to, 4, 6, and 8. The slots131may be symmetrically distributed on opposite sides of the lower plastic part13, and the fasteners24may be symmetrically distributed on opposite sides of the insulating support2.

By way of example, the top cover assembly1also includes an insulating sealing ring disposed between the terminal14and the cover plate11to ensure sealing of the accommodation space and avoid a short circuit.

In one or more embodiments, as shown inFIG.3, the top cover assembly1is provided with a liquid injection hole17. After the case3and the battery cover are assembled, an electrolyte can be injected into the accommodation space through the liquid injection hole17and serves as a channel for ion transfer. By way of example, the top cover assembly1also includes a seal5for blocking the injection hole17to prevent leakage of the electrolyte. By way of example, the seal5includes sealant plug that match the injection hole17and can be inserted into the injection hole17to enhance the sealing effect of power battery, and a sealing aluminum sheet that can be used to weld and seal the injection hole17.

In one or more embodiments, as shown inFIG.3, the top cover assembly1further includes an insulating plate16disposed on a side of the upper plastic part12away from the cover plate11to improve structural reliability.

For example, the case3may be an aluminum case, and the cover plate11may be an aluminum plate. The cover plate11is welded with the case3. During welding, pre-spot welding is performed. The number of welding spots for pre-spot welding may be, but not limited to,6EA,8EA, or10EA. The welding spots for pre-spot welding are symmetrically distributed. In one or more embodiments, the top cover assembly1further includes an insulating cover sheet15attached to the cover plate11to prevent a short circuit between the terminal14and the cover plate11due to external connection.

In one or more embodiments, the core4is coated with a protective film. An outer surface of the case3is coated with a protective film for insulation. With each of positive and negative tabs41ultrasonically welded, the core4is coated with a protective film to prevent the core4from being scratched when entering the case. The protective film may be of a polymer material with insulation, high temperature resistance and electrolyte corrosion resistance, and can be, but not limited to, a PET (polyethylene terephthalate) sheet with adhesive on one side.

In one or more embodiments, the tab41is coated with protective glue for insulation, so that a short circuit between the tab41and the aluminum case3can be effectively avoided. The core4coated with the protective film has an adhesive tape pasted at the tab41. A width of the adhesive tape exceeds the width of the tab41by 2˜10 mm. A part of the adhesive tape coated on the core4has a length of 5˜25 mm. A part of the adhesive tape coated on the tab41has a distance of 0˜5 mm from the welding area. The protective glue of the tab41can ensure complete insulation at a place where the tab41is attached to the aluminum case after the core enters the case.

The tab41of the core4may be laser welded with the corresponding top cover. The length and width of the welding wire are designed according to an overcurrent capacity required by the core to ensure the power requirement of the core. After the tab41is welded with the top cover, insulation treatment may be performed on the welding mark area by glue dispensing or adhesive tape pasting. An insulating glue or insulating adhesive tape shall be wide enough to completely cover the tab41in the width direction and be long enough to completely cover the tab41and the laser welding mark in the length direction.

In one or more embodiments, the core4is provided with a positive tab41and a negative tab41. The core4includes a positive active material, a negative active material, a positive current collector, a negative current collector, and a separator. The active materials provide a solid-phase reaction interface for the electrochemical reaction of the battery. The current collectors after gain/loss of electrons provide an electron channel for electron transfer. The separator can isolate electrons and allow ions to pass through.

In one or more embodiments, a welding mark is provided on the tab41. For example, the tab41can be flattened by a flat-tooth ultrasonic welding. Compared with deep-tooth welding, the flat-tooth ultrasonic welding will result in a larger welding mark area and a flatter welding mark. Then, the flattened tab41is welded with the lower terminal block141of the top cover assembly1by laser welding, which can enhance the strength of welding between the tab41and the top cover assembly1, improve an overcurrent capacity of the battery, and has high welding reliability. The tab41of each layer is welded, and the size of the welding mark matches the size of a welding wire used for laser welding of the tab41and the cover plate11. The size of ultrasonic flat welding can be, but not limited to, 10 mm*20 mm, 15 mm*20 mm, or 10 mm*30 mm, and the number of welding marks can be, but not limited to,1EA,2EA or3EA. One welding mark may be adopted if the welding mark area allows. The number of the cores4may be, but not limited to,1EA,2EA or3EA. Generally, the number of the cores4of a blade battery does not exceed2EA.

The insulating support2may be mounted after the tab41is bent and reshaped, which is beneficial for the insulating support2to effectively fix the reshaped tab41in the accommodation cavity P formed by the insulating support2and the lower plastic part13. In one or more embodiments, as shown inFIG.2, the tab41are bent in a Z-shape in the accommodation cavity P, so that the tab41is folded, which is convenient for putting the reshaped tab41into the accommodation cavity P when the insulating support2is mounted.

In one or more embodiments, the insulating support2abuts against the core4to fix the core4, which can ensure that the core4does not shake, thereby improving stability.

In one or more embodiments, as shown inFIG.4, the insulating support2includes two support bodies. The two support bodies are both connected to the top cover assembly1. The notch23is formed between the two support bodies. A recess may be provided on only one of the support bodies to form the notch23between the two support bodies. Alternatively, a recess may be provided on each of the support bodies to form the notch23between the two support bodies. Both of the support bodies are detachably connected with the lower plastic part13to improve connection reliability. The two support bodies can be called a first support body21and a second support body22, respectively. The first support body21and the second support body22may have different sizes, respectively, so that a position where the notch23is formed can be set according to the actual conditions. For example, the position can be set to correspond to a position of the folded tab41. For example, the first support body21and the second support body22may be made of the same material or different materials, respectively.

For example, the insulating support2is made of a material having sufficient hardness and having resistance to electrolyte corrosion and high temperature. The material may be, but not limited to, PP (polypropylene) material. A thickness of the insulating support2may be, but not limited to, 0.5 mm, 1.0 mm, 1.5 mm or 2.0 mm. The height of the insulating support2matches the height of the lower plastic part13. For example, as shown inFIG.4, the insulating support2is provided with through holes25communicating with the accommodation cavity P. Each through hole25may be, but not limited to, in a circular shape or a square shape. The through holes25are designed to facilitate free flow of the electrolyte in the inner space of the core.

One or more embodiments provide a process of manufacturing a core4, including the following steps. In the first step of homogenizing positive and negative electrodes, the positive active material, the negative active material, a conductive agent and a binder are uniformly dispersed into a solvent at a certain mass ratio. In the second step of coating the positive and negative electrodes, the uniformly dispersed positive and negative electrode slurry is stably coated on positive and negative current collectors. In the third step of preparing positive and negative electrode sheets, the coated positive and negative electrode sheets are rolled to the specified thickness and then cut to a specified size. In the fourth step of winding (or laminating) and assembling, the prepared positive and negative electrode sheets are wound (or laminated) into the core4that is then assembled into a battery. In the fifth step of baking, the assembled battery is baked in the vacuum oven to the specified moisture value. In the sixth step of injection, the electrolyte is injected into the battery, and then the battery is let stand until the electrolyte completely infiltrates the electrode sheets. In the seventh step of formation, the battery is activated, and the gas generated by side reaction in the battery is discharged by pumping negative pressure. In the eighth step of dividing the capacity, the formed battery is sealed and welded, and the capacity is divided according to the preset process.

One or more embodiments provide a process of assembling a power battery, including the following steps S1-S13.

At step S1, a positive tab41and a negative tab41of a core4are respectively welded through flat-tooth ultrasonic welding process.

At step S2, the core4is coated with a protective film.

At step S3, the positive tab41and the negative tab41are pasted with protective glue.

At step S4, the tab41is welded to a top cover assembly1r, the tab is provided with a welding mark, and the welding mark is coated with insulating glue (it may be the positive tab41or the negative tab41first).

At step S5, the welded tab41is bent and reshaped in a Z-shape.

At step S6, the insulating support2is mounted. The first support body21and the second support body22of the insulating support2are successively clamped to the lower plastic part13, and the reshaped part of the tab41is completely accommodated in the cavity formed by the two support bodies and the lower plastic part13and is completely isolated from the core4.

At step S7, the core4with the insulating support2is put into case3.

At step S8, the top cover assembly1is fitted to the case3to close the case3, and the cover plate11is fixed to the case3by pre-spot welding with laser.

At step S9, the tab41on another side of the core4is laser welded to the top cover assembly1and then an insulating glue is pasted to completely cover the welding mark and the tab41.

At step S10, the welded tab41is bent and reshaped in a Z-shape, so that the tab41is folded.

At step S11, the insulating support2is mounted. The first support body21and the second support body22of the insulating support2are successively clamped to the lower plastic part13, so that the fastener24of the insulating support2is completely clamped into the slot131of the lower plastic part13, and the reshaped part of the tab41is completely accommodated in the accommodation cavity P formed by the insulating support2and the lower plastic part13and is completely isolated from the core4.

At step S12, the top cover assembly1is fitted to the case3to close the case3, and the cover plate11is fixed to the case3by pre-spot welding with laser. The number of welding spots may be consistent with the number of spots of the above-mentioned pre-spot welding for the cover plate11.

At step S13, the cover plate11is fully welded to the case3by laser welding so as to ensure that the welding area is completely sealed.