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CN-121983743-A - Battery cell and battery pack

CN121983743ACN 121983743 ACN121983743 ACN 121983743ACN-121983743-A

Abstract

The invention relates to the technical field of batteries, in particular to a battery cell and a battery pack. The battery cell comprises a first discharging position and a second discharging position which are arranged on a shell, wherein the first discharging position is arranged below the second discharging position and corresponds to the position containing electrolyte in the battery cell, a notch groove is formed in the shell to reduce the thickness of the first discharging position, a pressure release piece is arranged on the second discharging position, a notch part is arranged on the pressure release piece, and the opening pressure of the notch groove is smaller than that of the notch part. According to the invention, partial electrolyte can be released in advance before the notch part on the pressure release part is cracked, so that less electrolyte is in the battery cell after the pressure release part is opened, the strength of thermal runaway thermal reaction of the battery cell is reduced, and the safety performance of the battery cell and the battery pack is improved.

Inventors

  • LI ZHAOHUA
  • LIU YOUJIAN
  • CHEN ZHENGXU
  • XU YADONG

Assignees

  • 蜂巢能源科技股份有限公司

Dates

Publication Date
20260505
Application Date
20260407

Claims (10)

  1. 1. A kind of electric core, characterized by comprising the following steps: the battery cell comprises a battery cell, a shell, a first discharging position and a second discharging position, wherein the first discharging position is arranged below the second discharging position and corresponds to the position of the battery cell for containing electrolyte; a scoring groove which is arranged on the shell to thin the thickness of the first discharging position; And the pressure release part is arranged at the second discharge position, a notch part is arranged on the pressure release part, and the opening pressure of the notch groove is smaller than that of the notch part.
  2. 2. The cell of claim 1, wherein the first drain is disposed on a bottom or bottom wall of a side wall of the housing and the second drain is disposed on a top wall of the housing after the plurality of cells are assembled into a cell module.
  3. 3. The cell of claim 1 or 2, wherein the first drain and the second drain are disposed on different surfaces of the housing.
  4. 4. The cell of claim 1, wherein the maximum internal pressure of the cell for normal charge and discharge is P1, the opening pressure of the score groove is P2, and the opening pressure of the score part is P3, and P3-0.2mpa > P2> p1+0.2mpa.
  5. 5. The cell according to claim 1, wherein one of the outer surface and the inner surface of the case is formed as a first surface and the other is formed as a second surface, the score groove is formed by recessing inward from the first surface, and a dimension of a groove bottom of the score groove and the second surface in a thickness direction of the first discharge site is L, and L is not less than 40 μm.
  6. 6. The cell of claim 1, wherein the housing comprises a welded housing and cover plate; The notch groove is arranged on the cover plate, the distance between the notch groove and the edge of the cover plate is M, and M is more than or equal to 3mm, or the notch groove is arranged on the shell wall of the shell, and the distance between the notch groove and the edge of the shell wall on which the notch groove is arranged is M, and M is more than or equal to 3mm.
  7. 7. The cell of claim 1, wherein the first vent is formed with a protrusion disposed around a circumferential outer edge of the score groove, the protrusion having a height dimension E of 0.5mm or more.
  8. 8. The cell of claim 7, wherein the projections and the score grooves are spaced apart by a distance F, F being greater than or equal to 1mm, on a plane parallel to the first discharge location.
  9. 9. The cell of claim 1, wherein an opening area of the score portion is greater than an opening area of the score groove.
  10. 10. A battery pack comprising the cell of any one of claims 1 to 9.

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 The outside structure of electric core includes apron and casing, and in the electric core course of working, especially under the unusual circumstances such as overcharging, short circuit, high temperature, the inside electrolyte of electric core can decompose and produce a large amount of gases, leads to the inside pressure of electric core to rise, after the pressure exceeds the withstand voltage scope of the outside structure of electric core, can appear cracking and even the condition of explosion. Therefore, the pressure relief structure on the battery cell is a very important safety component, and a part of the battery cell pressure relief components adopt explosion-proof valves, and can be automatically opened before the internal pressure of the battery cell reaches a dangerous value, so that internal gas is released to realize pressure relief, and physical explosion of the battery is avoided. After thermal runaway occurs in the cell, the main source of heat generation is the reaction and interaction of the anode and cathode materials and the electrolyte. In the overcharge test process, the side reaction of the battery cell is continuously accumulated, the heat production and the gas production are in a continuously aggravated state, when the pressure of the battery cell reaches a critical value, the explosion-proof valve is opened and then part of electrolyte is sprayed out, and the overcharge can be stopped when the overcharge test is continued and a thermal runaway judgment condition is reached. The electrolyte sprayed out instantly after the explosion-proof valve is opened can not participate in the heat generation of the subsequent thermal runaway reaction. However, after the explosion-proof valve is opened, the internal pressure and the external pressure can be quickly approximate, so that continuous spraying of electrolyte in the battery cell is difficult to realize, and the reduction of thermal runaway reaction heat is not facilitated. Disclosure of Invention Therefore, the application aims to provide a battery cell and a battery pack, so as to solve the problems that when an explosion-proof valve on the battery cell is opened, electrolyte can be sprayed out, and as the pressure inside and outside the battery pack is quickly close, the electrolyte in the battery pack is difficult to continuously spray out, so that the heat generation quantity of the battery cell is increased, and the risk of thermal runaway is increased. The first aspect of the present invention provides a battery cell, which comprises: the battery cell comprises a battery cell, a shell, a first discharging position and a second discharging position, wherein the first discharging position is arranged below the second discharging position and corresponds to the position of the battery cell for containing electrolyte; a scoring groove which is arranged on the shell to thin the thickness of the first discharging position; And the pressure release part is arranged at the second discharge position, a notch part is arranged on the pressure release part, and the opening pressure of the notch groove is smaller than that of the notch part. Preferably, after the plurality of electric cores are assembled into the electric core module, the first discharging position is arranged on the bottom or the bottom wall of the side wall of the shell, and the second discharging position is arranged on the top wall of the shell. Preferably, the first discharge location and the second discharge location are disposed on different surfaces of the housing. Preferably, the maximum internal pressure of the normal charge and discharge of the battery cell is P1, the opening pressure of the notch groove is P2, the opening pressure of the notch part is P3, and the pressure of P3-0.2mpa > P2> P1+0.2mpa. Preferably, one of the outer surface and the inner surface of the shell is formed into a first surface, the other surface is formed into a second surface, the notch groove is formed by inward recessing of the first surface, and the sizes of the groove bottom of the notch groove and the second surface in the thickness direction of the first discharge position are L, wherein L is more than or equal to 40 mu m. Preferably, the housing comprises a casing and a cover plate which are welded together; The notch groove is arranged on the cover plate, the distance between the notch groove and the edge of the cover plate is M, and M is more than or equal to 3mm, or the notch groove is arranged on the shell wall of the shell, and the distance between the notch groove and the edge of the shell wall on which the notch groove is arranged is M, and M is more than or equal to 3mm. Preferably, the first discharging position is provided with a protrusion arranged around the circumferential outer edge of the notch