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CN-121688150-B - Battery cell and battery pack

CN121688150BCN 121688150 BCN121688150 BCN 121688150BCN-121688150-B

Abstract

The invention relates to the technical field of batteries and discloses a battery cell and a battery pack, wherein the battery cell comprises a battery cell shell, a battery cell cover and a battery pack, wherein the battery cell shell is provided with a containing cavity and an opening communicated with the containing cavity; the heat-shrinkable film is sleeved on the periphery of the pole group and is coated on the pole group after being heated, through holes are formed in the heat-shrinkable film, and the through holes are located on large surfaces on two sides of the heat-shrinkable film along the Z direction. According to the invention, through the through holes are formed in the heat shrinkage film, when electrolyte is injected into the electrode group, the electrolyte can flow into the electrode group from the through holes, so that the infiltration effect of the electrolyte is improved, the electrolyte can be infiltrated into the electrode group rapidly and sufficiently, lithium precipitation of the battery cell is avoided, and the service performance of the battery cell is improved. And the through holes are arranged on the large surfaces of the two sides of the heat shrinkage film, so that the short circuit risk in the battery cell can be effectively reduced, the electrical performance of the battery cell is ensured, and the battery cell can work normally.

Inventors

  • LIU JIE
  • JIANG ZHEN

Assignees

  • 蜂巢能源科技股份有限公司

Dates

Publication Date
20260512
Application Date
20260212

Claims (7)

  1. 1. A kind of electric core, characterized by comprising the following steps: the battery cell shell is provided with a containing cavity and an opening communicated with the containing cavity; A pole group mounted in the accommodation chamber through the opening; The thermal shrinkage film is sleeved on the periphery of the pole group and is coated on the pole group after being heated; the heat-shrinkable film is provided with through holes, and the through holes are positioned on the large surfaces on two sides of the heat-shrinkable film along the Z direction; the aperture d of the through hole is more than or equal to 1mm and less than or equal to 4mm; the width w of the pole group is more than or equal to 50mm and less than or equal to 300mm, the distance L5 between the through hole and the central line of the pole group is more than or equal to 4mm and less than or equal to 146mm, and the L5/(w/2) is more than or equal to 0.4 and less than or equal to 0.8; The section perimeter Z1 of the pole group is 150mm or less and is 450mm or less, the clearance L7 between the heat-shrinkable film and the pole group is 0.5mm or less and is 10mm or less after the heat-shrinkable film is sleeved into the pole group, the heating shrinkage rate D of the heat-shrinkable film is 3% or less and is 40% or less and 4mm or less (Z1+4L7) x D-4L7 is 40mm or less.
  2. 2. The cell of claim 1, wherein, along the X-direction, both ends of the heat shrink film are provided with folds, and the folds are attached to the end faces of the pole groups.
  3. 3. The cell of claim 2, wherein the width L1 of the fold satisfies 1mm ∈l1+.50 mm.
  4. 4. The cell of claim 2, wherein the spacing L2 between the folds in the Z direction is 3mm +.l2 +.20 mm.
  5. 5. The cell of claim 1, wherein a distance L3 between the through hole and both sides of the electrode group in the X direction is 3mm or less and L3 or less and 297mm is satisfied, and a distance L4 between the through hole and both sides of the electrode group in the Y direction is 3mm or less and L4 or less and 297mm is satisfied.
  6. 6. The cell of claim 1, wherein a distance L6 between two adjacent through holes in the X direction satisfies 10mm +.l6 +.250 mm.
  7. 7. A battery pack, comprising: a case; a plurality of the cells of any one of claims 1-6, a plurality of the cells being housed in the case.

Description

Battery cell and battery pack Technical Field The invention relates to the technical field of batteries, in particular to a battery cell and a battery pack. Background Along with the increasing maturity of new energy battery technology, new energy battery is widely applied to electric automobile and energy storage field as power battery, therefore the performance and the security requirement of new energy battery are increasing. The traditional new energy battery such as a blade lithium battery core is characterized in that a thermal shrinkage film is coated on the periphery of a pole group, then the pole group is plugged into a battery core shell, and the pole group is packaged in the battery core shell through assembling, welding and sealing of a cover plate and the battery core shell, wherein the thermal shrinkage film plays a role in avoiding short circuit between the pole group and the battery core shell and protecting insulation and voltage resistance. The battery core is led out of the positive electrode post and the negative electrode post through the cover plate to realize charge and discharge. However, in the related art, when the heat shrinkage film is coated on the electrode set, the heat shrinkage film is too airtight to wrap the electrode set, so that the electrolyte cannot infiltrate into the electrode set rapidly and sufficiently, and lithium is separated from the battery cell, so that the electrical performance of the battery cell is abnormal. Disclosure of Invention In view of this, the invention provides a battery cell and a battery pack, so as to solve the problem that the electrolyte cannot infiltrate into the inside of the electrode group rapidly and sufficiently, so that the electrical performance of the battery cell is abnormal. In a first aspect, the present invention provides a cell comprising: the battery cell shell is provided with a containing cavity and an opening communicated with the containing cavity; A pole group mounted in the accommodation chamber through the opening; The thermal shrinkage film is sleeved on the periphery of the pole group and is coated on the pole group after being heated; the heat shrinkage film is provided with a through hole, and the through hole is positioned on the large surface at two sides of the heat shrinkage film along the Z direction. The battery cell has the beneficial effects that the thermal shrinkage film is sleeved on the peripheral side of the pole group, and the thermal shrinkage film is heated and shrunk to be tightly coated on the pole group, so that the pole group can be prevented from being scratched in the process of placing the pole group into the battery cell shell, the thermal shrinkage film also plays a certain insulating and protecting role, and the condition of short circuit caused by contact between the pole group and the battery cell shell is avoided. Through set up the through-hole on the pyrocondensation membrane, when pouring into electrolyte to the polar group inside, the electrolyte can follow the through-hole and flow into the polar group inside to increase the infiltration effect of electrolyte, make the electrolyte can be quick abundant infiltrate to the polar group inside, in order to avoid the battery cell to deposit lithium, thereby promote the performance of battery cell. Because the pole pieces are easy to leak outwards on the narrow side surfaces of the pole groups, and the active substances of the pole pieces are easy to fall off from the narrow side surfaces, the short circuit risk is increased, and therefore, the through holes are arranged on the large surfaces on the two sides of the heat shrinkage film, the short circuit risk in the battery core can be effectively reduced, the electrical performance of the battery core is ensured, and the battery core can work normally. In an alternative embodiment, along the X direction, two ends of the heat-shrinkable film are respectively provided with a folded edge, and the folded edges are respectively attached to the end faces of the pole groups. In an alternative embodiment, the width L1 of the folds is 1 mm≤L1≤50mm. In an alternative embodiment, the distance L2 between the folds in the Z direction is 3 mm≤L2≤20mm. In an alternative embodiment, the aperture d of the through hole satisfies 1 mm≤d≤5 mm. In an alternative embodiment, the distance L3 between the through hole and the two sides of the pole group along the X direction is less than or equal to 3mm and less than or equal to 297mm, and the distance L4 between the through hole and the two sides of the pole group along the Y direction is less than or equal to 3mm and less than or equal to 4 and less than or equal to 297mm. In an alternative embodiment, the width w of the pole group is equal to or less than 50mm and equal to or less than 300mm, the distance L5 between the through hole and the central line of the pole group is equal to or less than 4mm and equal to or less than 146mm, and the ratio of L5/(w/2) i